Efficiency drops as the temperature delta goes down. The trick is maintaining that difference. That section of the article is a bit misleading. Even really exp

Efficiency drops as the temperature delta goes down. The trick is maintaining that difference. That section of the article is a bit misleading. Even really expensive stoves are only about 95% efficient. You need some heat loss out the chimney for the thing to work. I'd guess that stoves typically in use in the rural global south are much less